Charge pump circuits are well known in the art. A charge pump circuit is used to pump or increase an input voltage to a higher voltage. Typically they can be found in use in non-volatile memory semiconductor devices. During the operation of program and/or erase, the voltage must be higher than the input voltage. Hence a charge pump circuit is used.
In the prior art, a charge pump circuit uses a capacitor to store or transfer charges. Active elements such a MOS transistors are used to pump charges to and from the capacitor to increase the output voltage of the charge pump circuit. Heretofore, one of the problems of the prior art is that a capacitor takes up much room in an integrated circuit die. For non-volatile memory devices, the non-volatile operating voltages remains essentially unchanged as the technology scaled down to smaller node. As the scale of integration increases for active elements, the passive elements, such as capacitors, remain unscalable due to unchanged operating voltages, and proportionally they take up a greater percentage of the real estate of the integrated circuit die. Hence it is desirable to increase the capacitance of a capacitor in a given volume of space.